Patent GB-1383962-A (GB)
Title: Dimensional measuring apparatus and methods
IPC: G07C3/14
Filed: 1972-03-28
Abstract: 1383962 Measuring lean of articles EMHART ZURICH SA 28 March 1972 [22 April 1971] 14360/72 Heading G1A [Also in Division G4] Apparatus for generating an output signal from two input signals comprises two storage means each for storing one of the two inputs, a pulse generator and two circuits each having as inputs, the pulse generator output and one of the storage units output, each of which circuits is adapted to supply as many pulses from the generator as corresponds with the square of the corresponding input signal stored in the storage unit, and an adding network connected with the output of each of the circuits, and means to provide the input signals, each signal consisting of a pulse train in which the number of pulses is proportional to twice the length of the projection on to a straight line of a rector, from a direction making a predetermined angle with the line, the angles being 45 degrees and 135 degrees for the respective inputs. Apparatus, for detecting the lean of an article passing on a moving conveyer is disclosed, i.e. the deviation of a vector connecting the centre of the base with that of the top, from the vertical, and comprises photo-electric elements 15-18 (Fig. 1) arranged symmetrically about a vertical 12 each pair adapted to give outputs when both elements are simultaneously obscured by the article 11. The output from cells 17, 18 is an elongate pulse and that from 15, 16 is a spike which, in the event of scanning an article having no lean, will occur in the centre of the former pulse. The elongate pulse is adapted to gate clock pulses, from a generator associated with the motion 13 of the conveyer to a counter and the spike is adapted to reverse the direction of count such that a zero count at the end of the scanning process will mean the article is symmetrical about the vertical 12, any other count will be proportional to twice the projected length l (Fig. 1). In order to quantify lean vectors in any direction two mutually perpendicular photo-electric assemblies are used arranged at 45 degrees and 135 degrees to the direction of travel of the article. The corresponding counters are indicated as 46, 47 in Fig. 6 and it may be shown that with this geometrical arrangement, the appropriate quantification is obtained by a squaring and adding step. After a scanning has taken place, a start signal is applied to an oscillator 40 which produces a square wave signal 73 which is differentiated at 41 and 42 to produce two phase-displaced signals 74, 75 respectively which are passed through AND gates 55, 65 and 43, and are applied to counters 53, 63. The outputs of these counters are applied to respective comparators 51, 61 for comparison with the counts held at 46, 47 and a pulse is applied to further counters 54, 64 whenever the comparator recognizes equality, which further counters are associated with further comparators 52, 62 also connected with counters 46, 47 and pulses are issued to close the gates 55, 65 after a string of pulses proportional to the square of the numbers held at 46, 47 has been passed. The AND gate 43 serves to add these pulses which are passed to a divider 44 and to a counter 45 which is also pre-set with a reference count whereby an output 76 is derived if the count is greater than this pre-setting.